1. Technical Field
The present invention relates to a sheet presence detecting apparatus, an image reading apparatus, a method for detecting a sheet presence and a method for reading an image in a sheet, in which the presence of the sheet is detected by using of a CCD (Charge Coupled Device) sensor. In particular, the present invention relates to a sheet presence detecting apparatus, an image reading apparatus, a method for detecting a sheet presence and a method for reading an image in a sheet, in which the sheet is mounted on a sheet mounting glass and the sheet mounting glass is covered with a sheet cover and then, the sheet presence is detected by using the CCD sensor.
2. Background Art
There is an apparatus which determined whether a sheet is mounted on a sheet mounting glass by using a CCD sensor. In case that the CCD sensor is used in order to detect the sheet presence, it is not necessary to install additionally a specific sensor for detecting the sheet presence. Accordingly, it is possible to lower cost of the apparatus.
However, when the CCD sensor is used for the detection of the sheet presence, the detection result on the sheet presence is affected by variation due to a kind of the sheet, a state of a sheet cover, a speed of closing the sheet cover or the like. A related art 1 (Japanese Patent Application Laid-Open No. 2000-184144) discloses an image reading apparatus which determines a kind of a sheet cover when power is supplied initially to the apparatus, and detects an edge of the sheet based on darkness information which is corresponding to the determination of the kind of the sheet cover.